NMR clinical analyzers have been used by LipoScience, Inc., located in Raleigh, N.C., to generate quantitative measurements of biosamples that assess a patient's risk of coronary artery disease (“CAD”) and/or diabetes using NMR-derived (quantitative analysis) lipoprotein measurements. U.S. Patent Application Publication No. US2005/0222504 describes exemplary NMR clinical analyzers. U.S. Pat. No. 6,518,069 describes examples of Type II diabetes risk assessments and NMR glucose measurements. U.S. Patent Application Publication No. US2010/0100334 describes Lipoprotein Insulin Resistance Indexes that may also be useful for assessing a risk of developing diabetes. The contents of the above-referenced patents and patent application publications are hereby incorporated by reference as if recited in full herein.
It is well known that NMR analyzers are temperature sensitive. Ambient temperature fluctuation can result in unreliable quantitative measurements. In the past, NMR analyzers, particularly those used for quantitative measurements, were required to be kept in rooms with controlled temperatures, typically controlled to be within about +/−one (1) degree Celsius, to address this problem. Indeed, the two largest NMR spectrometer manufacturers (Agilent Technologies, Inc. and Bruker BioSpin Corp.) state in their site operational manuals that while the instruments can operate from 17-24 degrees C., for optimal performance the room temperature must be regulated, e.g., the room temperature should be maintained to within +/−1 degree C. This tight temperature control is often maintained in dedicated NMR labs but it is not common in clinical labs such as those in hospitals or commercial lab environments, as many commercial or clinical laboratory environments can fluctuate in temperature in different zones and/or over time. The change in temperature affects the sensitivity and phase performance of NMR instrument and can therefore negatively affect the accuracy of a quantitative measurement.
Thus, there is a need for NMR clinical analyzers that can operate in environments that may fluctuate in ambient temperature over time (e.g., hourly, daily, weekly, monthly and the like) and/or vary over a wide range of temperatures and still generate accurate quantitative measurements.